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AI Token Counter

Count words, characters, and estimated tokens by AI model.

OpenAI Cost Calculator

Estimate monthly spend by model, tokens, and usage tier.

Claude API Cost Calculator

Estimate Anthropic Claude API costs by model and monthly call volume.

AI Prompt Cost Estimator

Paste your prompt to count tokens and estimate cost across GPT-4o, Claude, and more.

LLM Cost Calculator

Estimate and compare AI API costs across GPT, Claude, Gemini, DeepSeek, and Mistral.

AI Prompt Examples Library

Browse 100+ free AI prompt examples for ChatGPT, Claude, and Gemini. Searchable by category.

Vortenza Humanizer

Transform AI-generated content into natural, human-sounding text that passes GPTZero, Turnitin, and Originality.ai detection. Free, no signup.

Vortenza Writer

Generate original articles written in human style from scratch. No AI patterns, no detection issues.

AI Detection Checker

Check if your text will be flagged as AI-written by GPTZero, Turnitin, or Originality.ai. Get a score instantly.

Plagiarism Checker

Check your content for plagiarism with n-gram analysis and uniqueness scoring. Free, no word limit.

Cold Email Subject Line Tester

Score your cold email subject lines for spam words, length, and open rate potential.

SPF DKIM DMARC Checker

Check your domain SPF, DKIM, and DMARC DNS records with color-coded results and plain-English explanations.

DMARC Record Generator

Generate a valid DMARC TXT record for your domain with plain-English explanations for every setting.

Email Spam Score Checker

Check your email subject and body for spam trigger words, formatting issues, and deliverability risks.

Email Duplicate Checker

Find and remove duplicate emails from your lead lists. Upload a blocklist and leads CSV to get a clean unique list ready for cold email campaigns.

Tax

Federal Income Tax Estimator

Project federal tax owed with brackets and deductions.

Freelance Rate Calculator

Calculate your hourly rate, day rate, and project pricing with real freelancer business math. Supports 10 countries.

Mortgage Payment Calculator

Monthly payment, interest, and amortization breakdown.

Compound Interest Calculator

See how savings grow with contributions and APY.

Salary to Hourly Calculator

Convert annual salary to hourly rate and vice versa. See gross and after-tax pay by hour, day, week, and month.

Net Worth Calculator with Age Comparison

Calculate your net worth and compare to US median for your age group. Track assets vs liabilities and set a growth goal.

Debt Snowball vs Avalanche Calculator

Compare the debt snowball and avalanche payoff methods side by side. See which saves more interest and pays off faster.

Free Invoice Generator

Create professional freelance invoices instantly. Add line items, tax, and notes. Download print-ready. No signup.

JSON Formatter & Validator

Beautify, minify, and validate JSON with live syntax highlighting. Runs entirely in your browser.

Regex Tester

Test and debug regular expressions with live match highlighting, flag toggles, capture groups, and example patterns.

Base64 Encoder and Decoder

Encode or decode Base64 strings instantly. Supports text, files, and URL-safe mode. All processing in your browser.

CSS Gradient Generator

Generate linear, radial, and conic CSS gradients with live previews, color stops, angle controls, and preset swatches.

Cron Job Schedule Builder

Build cron expressions visually with plain-English explanations. See next 5 run times and copy instantly.

JWT Decoder and Inspector

Decode JWT tokens instantly. View header, payload, and claims. Check expiry status and get security analysis. Browser-only.

Unix Timestamp Converter

Convert Unix timestamps to human-readable dates instantly. Supports seconds, milliseconds, UTC, ISO dates, and timezone conversion. Free, browser-only.

Converters

Unit Converter

Length, weight, temperature, and more.

URL Encoder and Decoder

Encode or decode URLs and query strings instantly. Parse URL components and build query strings. Free, browser-only.

SQL Formatter and Validator

Format, beautify, and minify SQL queries online. Syntax highlighting, dialect support (MySQL, PostgreSQL, SQLite, SQL Server), and validation. Free, browser-only.

Freelance Contract Generator

Generate a professional freelance contract covering scope, payment, IP ownership, and termination. Download ready. Free, no signup.

Markdown to HTML Converter

Convert Markdown to HTML with a live preview. Supports tables, code blocks, task lists, and all GitHub Flavored Markdown. Free, no signup.

Emergency Fund Calculator

Calculate how much emergency fund you need based on your expenses, income type, and risk factors. See your timeline to goal.

Inflation Calculator

Calculate inflation-adjusted value using historical US CPI data from 1913 to 2026. See purchasing power changes and average annual rates.

AI Writing Cost per Article Calculator

Estimate API cost to write one article with GPT-4o, Claude, Gemini, or DeepSeek. Compare all 12 major models side by side.

DeepSeek API Cost Calculator

Calculate DeepSeek V3 and R1 API costs with prompt caching. Compare vs GPT-4o, Claude Haiku, and Gemini Flash.

HTTP Status Codes Reference

Complete reference for all 63 HTTP status codes with descriptions, causes, and developer tips. Filter by category or search by code number.

JSON to CSV Converter

Convert JSON arrays to CSV instantly in your browser. Supports nested objects with dot notation, custom delimiters, and instant download. No signup required.

Word Count and Readability Analyzer

Free readability checker with Flesch Reading Ease, Flesch-Kincaid Grade Level, ARI score, reading time, and top word frequency analysis.

Password Strength Checker

Free password strength checker with crack time estimate, entropy calculator, and strong password generator.

Color Contrast Checker WCAG

Check color contrast ratios for WCAG AA and AAA compliance. Get instant pass/fail for normal text, large text, and UI components.

Regex Explainer

Paste any regex pattern and get a plain English explanation token by token. Test matches and see captured groups.

AI System Prompt Leakage Tester

Test your AI system prompt for security vulnerabilities. Runs 8 adversarial attacks and shows what information users could extract.

Cold Email Infrastructure Planner

Plan cold email infrastructure: domains, inboxes, warmup schedule, and monthly costs. Free calculator for agencies and B2B teams.

Upwork Proposal Win-Rate Calculator

Calculate your Upwork break-even win rate, profit per project, and monthly net income using the 2025 variable fee model.

SPF Record Generator

Generate a valid SPF record for Google Workspace, Microsoft 365, SendGrid, and more. Includes DNS lookup counter and copy-ready output.

Email Header Analyzer

Analyze email headers to check SPF, DKIM, DMARC authentication, trace delivery hops, detect spam signals, and get a deliverability score.

Email Deliverability Checker

Check your domain SPF, DKIM, and DMARC DNS records instantly. Get a 0-100 deliverability score with actionable fixes for every issue. Free, no signup.

Guides

Freelance

Upwork Fees 2026: What Freelancers Actually Pay (Complete Guide)

Upwork fees in 2026 fully explained: variable service fees (0-15%), Connect costs, withdrawal fees, hidden proposal costs, and real profit examples with acquisition cost math.

GPT-4o vs Claude vs Gemini: Real API Cost Comparison (2026)

GPT-4o vs Claude vs Gemini API cost comparison for 2026. Real monthly costs for chatbots, agents, and RAG apps. Token pricing tables, 4 real examples, and a provider recommendation by workload.

Regex Cheat Sheet 2026: Copy-Paste Examples for Developers

25 copy-paste regex patterns for email, URL, password, phone, dates, and more. Syntax tables, common mistakes, performance tips, and a one-minute audit checklist.

Cron Job Syntax Guide 2026: Complete Examples and Cheat Sheet

Complete cron job syntax guide for 2026. Field values, 20 common cron expressions, real-world examples, common mistakes, and a troubleshooting table for failing cron jobs.

JWT Tokens Explained: How to Decode Them Safely (2026)

JWT tokens explained for 2026. Structure, decode vs verify, security mistakes, real examples, and how to safely inspect JWT payloads without trusting them.

SPF Setup Guide for Google Workspace (2026)

How to create and publish an SPF record for Google Workspace in 2026. Step-by-step DNS setup for Cloudflare, Namecheap, and GoDaddy, plus verification and common error fixes.

SPF, DKIM, and DMARC Explained in Plain English (2026)

SPF, DKIM, and DMARC explained without jargon. What each record does, how to check your setup, and why all three matter for inbox placement in 2026.

Net Worth by Age 2026: US Median Benchmarks (Federal Reserve Data)

Real US median net worth by age from the Federal Reserve's 2022 Survey of Consumer Finances. Benchmarks for every age group, real examples, and how to improve your net worth.

Read guide Freelance

How to Write a Freelance Invoice That Gets Paid (2026)

How to write a freelance invoice that gets paid faster in 2026. What to include, best payment terms, common mistakes, and how to follow up on late payments.

How to Set Up a DMARC Record (Step-by-Step Guide for 2026)

How to create and publish a DMARC TXT record in 2026. Covers p=none, p=quarantine, p=reject, DNS setup for Cloudflare and Namecheap, and how to verify it works.

Read guide Freelance

Freelance Contract Templates 2026: Free Examples and Essential Clauses

Freelance contract templates for 2026. What to include, the 7 most important clauses, how to prevent scope creep, and how to protect yourself from non-payment.

Emergency Fund Calculator: How Much Do You Need? (2026)

How much emergency fund you actually need in 2026. Real calculations for singles, families, and freelancers, plus what counts as an expense and where to keep the money.

Email Spam Filters Explained: What Triggers Them in 2026

How email spam filters work in 2026, what triggers them, and how to stop legitimate emails from landing in spam. Covers Gmail, Outlook, authentication, and content signals.

Email Deliverability Guide 2026: What It Is and How to Fix It

What email deliverability is, why emails land in spam, and how to fix it using SPF, DKIM, and DMARC in 2026. Benchmarks, checklists, and a free checker tool included.

DKIM Setup Guide for Microsoft 365 (2026)

How to enable DKIM in Microsoft 365 in 2026. Step-by-step DNS setup for Cloudflare, Namecheap, and GoDaddy, with CNAME record examples and common error fixes.

Cold Email Deliverability Guide 2026: How to Reach the Inbox

How to get cold emails into the inbox in 2026. Covers domain setup, email warmup, SPF/DKIM/DMARC for cold outreach, sending volume limits, subject line rules, and a full deliverability checklist.

LLM Cost Comparison 2026: Which AI API Is Actually Cheapest?

Real LLM API cost comparison for 2026. GPT-4o vs Claude 3.5 vs Gemini vs DeepSeek -- per-token prices, real-world scenarios, hidden costs, and which model is actually cheapest for your use case.

Debt Snowball vs Avalanche: Real Math Comparison (2026)

Debt snowball vs avalanche compared with real numbers. Which method saves more interest, which pays off debt faster, and which one most people actually stick with in 2026.

Unix Timestamp Explained: Convert, Read & Use Timestamps (2026)

Unix timestamps explained for 2026. What they are, how to convert them, seconds vs milliseconds, UTC vs local time, JWT exp fields, and common timestamp bugs.

Salary vs Hourly: Which Pays More After Taxes? (2026)

Salary vs hourly pay compared for 2026. Real after-tax examples, overtime math, benefits value, exempt vs non-exempt rules, and a career-by-career breakdown.

Read guide AI Cost

How to Reduce OpenAI API Costs: 7 Real Methods That Work (2026)

Reduce OpenAI API costs in 2026. Prompt optimization, model selection, caching, RAG optimization, and 3 real case studies showing 60-75% cost reductions.

Inflation Calculator Guide: Purchasing Power 1913-2026

How CPI works, what $100 from 1913 is worth in 2026, salary and home price comparisons, and how inflation affects savings and retirement. Real examples using BLS CPI data.

Gemini API Pricing 2026: Complete Cost Breakdown for Gemini 2.5 Pro, Flash, and Flash-Lite

Real Gemini API pricing for 2026. Gemini 2.5 Pro, Flash, and Flash-Lite token costs, free tier limits, context window pricing, and real-world cost scenarios for developers and teams.

Read guide Email Tools

Email List Hygiene Guide 2026: Clean Your List and Improve Deliverability

How to clean your email list in 2026. Hard bounce removal, engagement pruning, re-engagement campaigns, spam trap avoidance, and a step-by-step monthly hygiene workflow.

Base64 Encoding Explained: Encode, Decode and Common Uses (2026)

Base64 encoding explained for 2026. How it works, real examples in JavaScript and Python, JWT tokens, HTTP Basic Auth, common mistakes, and when not to use it.

Cost Per Token Explained: GPT vs Claude vs Gemini (2026)

Token pricing explained for 2026. What a token is, how much GPT, Claude, and Gemini charge per million tokens, and how to estimate real costs for your application.

How Much Does an AI Chatbot Cost in 2026? Complete Pricing Guide

Real AI chatbot costs for 2026. Build costs, monthly API fees, hidden costs, and ROI calculations for GPT, Claude, and Gemini-powered chatbots at every scale.

AI Agent Cost Breakdown (2026): What Businesses Actually Spend

Real AI agent costs for 2026. Build costs, monthly operating costs, hidden costs, and ROI calculations for sales, support, and operations agents at startup and enterprise scale.

ChatGPT vs Claude vs Gemini vs DeepSeek (2026): Which One Actually Wins?

Four AI tools, real tasks, honest results. Including the DeepSeek cost gap that changes the math for developers.

Prompt Engineering in 2026: What Actually Gets Better Results from ChatGPT and Claude

A practical prompt engineering guide: few-shot examples, chain of thought, how Claude and ChatGPT differ, negative constraints, and building a prompt library that compounds over time.

Compound Interest Explained: Formula, Real Examples, and the Rule of 72

A plain-language explanation of compound interest: the formula, real examples with actual numbers, why compounding frequency matters, and how to use the Rule of 72.

AI Detectors Are Guessing. Here's What I Learned

I got a 71% AI score on content I wrote myself. Then two other detectors gave completely different results.

How to Bypass AI Detection in 2026 (What Actually Works)

AI detectors are failing at alarming rates. Here's what actually changed in 2026, why old bypass tricks stopped working, and what structurally beats detection tools.

Freelance Rate vs Salary: The Real Financial Comparison (2026)

Real numbers on freelance vs salary: self-employment tax, hidden costs, utilization rates, and what you actually need to earn to match your current income.

How I Actually Invoice as a Freelancer Now (Because the Corporate Advice Doesn't Work)

I used Net 30, started at Invoice #1, and apologized in follow-up emails. Here is what I do instead.

Why I Now Send a Contract Before I Start Any Freelance Project

A practical freelance contract guide covering scope of work, kill fee clauses, revision limits, and what to do when clients push back.

Read guide Tax

Self-Employment Tax 2026: Complete Calculator Guide for Freelancers

What the 15.3% SE tax actually costs you, how to calculate it without spreadsheets, and the legal moves that bring it down.

Read guide Tax

1099 Tax Deductions Complete Guide for Freelancers 2026

My first freelance year I overpaid the IRS by $3,200. Here are the deductions that changed everything.

ChatGPT Plus vs Claude Pro vs Gemini Advanced 2026: Which $20/Month AI Is Worth It?

I subscribed to all three for 90 days. Here is the honest comparison for writers, developers, and freelancers.

How to Calculate Your Freelance Hourly Rate in 2026: The Formula That Actually Works

I charged $25/hour my first year and was losing money on every project. Here is the formula I wish I had from day one.

OpenAI API Pricing 2026: Complete Cost Guide

Real GPT-5, Claude, Gemini, and DeepSeek API costs for 2026, plus 7 proven ways to cut your bill by 70%.

Claude API Pricing 2026: Full Cost Breakdown

Haiku, Sonnet, and Opus per-token rates, prompt caching, batch discounts, and the model choices that actually reduce your bill.

What Is a Token in AI? (GPT-4, Claude, and Gemini Explained)

A plain-language explanation of AI tokens, context windows, and why token economics matter for anyone building with AI APIs.

Read guide Converters

Unit Converter Guide: Length, Weight, Temperature & Volume (2026)

A complete unit conversion reference for length, weight, temperature, and volume. Metric to imperial charts, quick formulas, and a free browser-based unit converter.

Regex for Non-Developers: Patterns That Save Hours (2026)

The 8 regex patterns that solve 90% of real non-developer text problems. How to use regex in VS Code and Google Sheets, with a free browser tester. No programming required.

What Is Perplexity and Burstiness in AI Writing? (2026 Guide)

The two numbers that determine if your writing sounds human. What perplexity and burstiness measure, why human writers get flagged, and how to improve both scores.

JSON Formatter Guide 2026: How to Read, Validate, and Fix JSON Errors Fast

What a JSON formatter actually does, the four most common JSON errors and how to fix them, and when to use a browser tool vs. the command line.

How to Check Plagiarism Before Publishing (2026 Guide)

Why clean content still gets flagged, what similarity scores actually mean, and the free tools worth using in 2026.

How to Calculate Your Mortgage Payment (2026 Guide)

The real mortgage payment formula including PITI, PMI, and escrow. Why your actual payment is $773 more than the bank quote, with real 2026 numbers and a free calculator.